Field of the Invention
The present invention relates to a temperature measurement apparatus for a sound signal converting device, the apparatus measuring temperature of a coil of the sound signal converting device. The invention also relates to a protection apparatus for the sound signal converting device, the apparatus having the temperature measurement apparatus and preventing rise in temperature of the coil in order to protect the sound signal converting device.
Description of the Related Art
Conventionally, as described in Japanese Unexamined Patent Publication No. 2008-292739, there is a keyboard musical instrument having a sound board, the instrument supplying an electric signal indicative of a musical tone generated by a tone generator in accordance with player's musical performance on a keyboard to a coil of a transducer which vibrates the sound board to vibrate the sound board in accordance with the electric signal indicative of the musical tone to generate a musical tone of a low tone volume.
Furthermore, Japanese Unexamined Patent Publication No. 2004-328954 discloses an apparatus which measures temperature of a coil of a motor for controlling automobile parts, and restricts driving of the motor in order to prevent burnout of the coil if the temperature of the coil has exceeded an acceptable value. For the coil temperature measurement, the voltage applied to the coil is detected, with the current passing through the coil being detected, so that the resistance value of the coil is calculated on the basis of the detected voltage and current to calculate the temperature of the coil in accordance with the calculated resistance value.